On Tue, Nov 19, 2019 at 04:02:48PM +1300, Thomas Munro wrote:
> On Tue, Nov 19, 2019 at 12:09 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > You should follow the logic in pg_wcswidth: compute PQmblen() first,
> > and bail out if it's more than the remaining string length, otherwise
> > it's ok to apply PQdsplen().
>
> Got it. I was worried that it wasn't safe to call even PQmblen(),
> because I didn't know a fact about all encodings: as described in the
> comment of pg_gb18030_mblen(), all implementations read only the first
> byte to determine the length, except for GB18030 which reads the
> second byte too, and that's OK because there's always a null
> terminator.
>
> > It might be a good idea to explicitly initialize last_prompt1_width to
> > zero, for clarity.
> >
> > Should the user docs explicitly say "of the same width as the most recent
> > output of PROMPT1", as you have in the comments? That seems a more
> > precise specification, and it will eliminate some questions people will
> > otherwise ask.
> >
> > LGTM otherwise.
>
> Done, and pushed. I also skipped negative results from PQdsplen like
> pg_wcswidth() does (that oversight explained why a non-readline build
> showed the correct alignment for PROMPT1 '%[%033[1m%]%M
> %n@%/%R%[%033[0m%]%# ' by strange concindence).
>
> Thanks all for the feedback. I think the new bikeshed colour looks good.
Please find attached some polka dots for the bike shed :)
Best,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778
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